Macrocyte subpopulations in hemochromatosis probands with HFE p.C282Y homozygosity: Clinical and laboratory associations.

BACKGROUND

The elevated average mean corpuscular volume (MCV) of adults with hemochromatosis and HFE p.C282Y (rs1800562) homozygosity is incompletely understood.

METHODS

We retrospectively measured percentages of small (100.0-109.9 fL) and large (110.0-200.0 fL) macrocytes in automated hematology analyzer erythrocyte volume histograms of hemochromatosis probands with p.C282Y homozygosity and iron overload without cirrhosis. We evaluated associations of small and large macrocyte percentages with age, sex, body mass index (BMI), daily alcohol consumption, diabetes, hemochromatosis arthropathy, transferrin saturation (TS), and serum ferritin (SF) at diagnosis.

RESULTS

There were 69 probands (46 men, 23 women) of mean age 49 ± 15 y. Median BMI was 27.5 kg/m2 (16.9, 46.3). Ten probands (14.5%) had diabetes and seven (10.1%) had arthropathy. Mean TS, SF, and MCV were 81 ± 14%, 791 ± 480 µg/L, and 95.5 ± 4.1 fL, respectively. Mean small and large macrocyte percentages were 17.9 ± 14.3 % and 31.3 ± 8.2 %, respectively. Correlations of small and large macrocyte percentages with age were significant (r69 = 0.3937; p = 0.0008 and r69 = 0.2634; p = 0.0288, respectively). The mean small macrocyte percentage of 11 probands who reported daily alcohol consumption was greater than that of the 58 other probands (20.6 ± 2.9 % and 17.4 ± 4.4 %, respectively; p = 0.0070). The correlation of large macrocyte percentages with TS was significant (r69 = 0.2661; p = 0.0271). Linear regressions confirmed these positive associations: small macrocyte percentages with age (p = 0.0012) and daily alcohol consumption (p = 0.0355); and large macrocyte percentages with age (p = 0.0306) and TS (p = 0.0247).

CONCLUSIONS

In HFE p.C282Y homozygotes, small macrocyte percentages are associated with age and daily alcohol consumption and large macrocyte percentages are associated with age and TS.